HS125 captain reported an near midair collision on arrival into ryy.

Attributes
ACN	1341950
Time
Date	201603
Local Time Of Day	1201-1800
Place
Locale Reference	RYY.Airport
State Reference	GA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	HS 125 Series
Operating Under FAR Part	Part 91
Flight Phase	Initial Approach
Route In Use	Visual Approach Direct
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Aircraft
Operating Under FAR Part	Part 91
Flight Phase	Initial Approach
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 40 Flight Crew Total 12500 Flight Crew Type 2000
Events
Anomaly	Conflict NMAC
Miss Distance	Horizontal 300 Vertical 200

Narrative:

On a re-positioning flight to ryy at 3000 ft atlanta ATC cleared us for a visual approach to runway 27. Shortly after; ATC called traffic for us at 1000-1100 o'clock and 2500 ft. I saw the traffic on TCAS but at this time had no visual. Watching said traffic on TCAS; I saw it go from 500 ft below to 400; 300; 200. TCAS gave us an RA and I complied. As I climbed; I got a visual on the aircraft. Though I saw the aircraft; I continued complying with the RA until we were at approximately 3800 ft. I asked ATC who the aircraft was and they told us they were not talking to them. While I realize he is running a business and we all share the airspace; keeping your 'head on a swivel' is definitely something everyone should practice. In his type of operation; I would suggest that he keeps open communications with atlanta and local towers.

Original NASA ASRS Text

Title: HS125 Captain reported an NMAC on arrival into RYY.

Narrative: On a re-positioning flight to RYY at 3000 ft Atlanta ATC cleared us for a visual approach to Runway 27. Shortly after; ATC called traffic for us at 1000-1100 o'clock and 2500 ft. I saw the traffic on TCAS but at this time had no visual. Watching said traffic on TCAS; I saw it go from 500 ft below to 400; 300; 200. TCAS gave us an RA and I complied. As I climbed; I got a visual on the aircraft. Though I saw the aircraft; I continued complying with the RA until we were at approximately 3800 ft. I asked ATC who the aircraft was and they told us they were not talking to them. While I realize he is running a business and we all share the airspace; keeping your 'head on a swivel' is definitely something everyone should practice. In his type of operation; I would suggest that he keeps open communications with Atlanta and local towers.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.